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Date: Thu, 30 Apr 2020 14:48:40 +0100
From: Darren Wise <darren@...ecorp.co.uk>
To: john-users@...ts.openwall.com
Subject: Re: Reduce CPU load. Is it possible?

Each core can run two threads I assume, four actual CPU cores equates to eight threads? HT? HyperThreading is active. However I even have a SUNmicrosystem CPU which is quadcore and runs 16 threads, four per core.. Wish Intel mastered that one.

Obviously I'm assuming here whatever CPU you are utilising can multi thread per CPU core too.

On 30 April 2020 10:34:42 BST, Solar Designer <solar@...nwall.com> wrote:
>On Wed, Apr 29, 2020 at 11:03:15PM +0000, oayz wrote:
>> I have 4 cores. Running all 4 as    start /affinity 0xffffffff
>\JOHN\run\john.exe
>>  (left side of plots) than with only cores 3 and 4 as    start
>/affinity 0xfffffffe \JOHN\run\john.exe
>> (right side)
>
>The message had a screenshot attached.  We don't use screenshots here,
>and the list is configured to automatically strip images.  Luckily,
>your
>description is good enough on its own, which is how it should be.
>
>> But in both cases JtR says "will use 4 OpenMP threads"
>
>That's what I suspected.  So don't use this approach, it is
>inefficient.
>Use OpenMP's own settings instead, like I had suggested.
>
>This discussion got me thinking: maybe we should add a john.conf
>setting
>to limit the number of threads.  It'll be the same as or similar to
>OMP_NUM_THREADS, but we'll be able to give people instructions that are
>independent of OS and shell.
>
>Alexander

-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.

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